Field of the Invention
The present invention relates to a printing plate unit.
Discussion of the Background
Examples of known printers include a configuration in which a printing plate is mounted on an outer periphery of a plate cylinder to be fixed to a plate drive shaft.
In the printer as described above, a sheet-type printing plate is mounted by winding around a plate cylinder in a state of fixed to the plate drive shaft. In such a case, a mounting work of a printing plate in the printer is troublesome, and it is difficult to mount reliably the printing plate to the plate cylinder.
In order to avoid such an event, the plate cylinder may be fixed to the plate drive shaft after a sheet-type printing plate has been mounted by being wound around the plate cylinder in a state of being demounted from the plate drive shaft. In such a case, since the plate cylinder has a significant weight, demounting and mounting operation of the plate cylinder with respect to the plate drive shaft are difficult.
The present inventor proposed a configuration in which a plate portion is provided on part of an outer peripheral surface of a plate body formed of a resilient member (for example, a metallic sheet) into a cylindrical shape and an engaging portion extending axially so as to project inward on an inner periphery of the plate body as a printing plate which can be mounted easily and accurately to a printer (See Japanese Unexamined Patent Application Publication No. 2009-285861).
This printing plate is used by being mounted on a printing plate mounting portion of a plate cylinder apparatus of the printer. For example, the printing plate mounting portion is provided with a plate cylinder portion provided fixedly on a plate drive shaft, and the printing plate is fitted to the plate cylinder portion from one end side. The printing plate can be mounted accurately and easily at a predetermined position of the plate cylinder by providing the plate cylinder portion with a circumference direction positioning groove in which the engaging portion of the printing plate is fitted from the one end side and an axial direction positioning stopper to which an end portion of the printing plate abuts on an outer periphery thereof. The printing plate can be demounted easily from one end side of the plate cylinder portion.